Chih-Ping Chen1
Ming Chi University of Technology1
Chih-Ping Chen1
Ming Chi University of Technology1
Near-Infrared (NIR) small molecule acceptor with the absorption of up to wavelength of 1000nm attracted much attention for organic photodetectors (OPD) and the biometric application. We evaluate the IEICO-4F as third component for PffBT4T-2OD: PC<sub>71</sub>BM based OPD to having efficient NIR response and greatly suppressing leakage current at reverse bias. By variation of the blend ratios and thickness (250-600nm), we realized an NIR OPD with ultralow dark current density (J<sub>D=</sub>9.43 nA cm<sup>–2</sup>) with an ultrahigh detectivity (D*= 2.7 ×10<sup>12</sup> Jones (850 nm)). Furthermore, the OPD shows consistent response, good reproducibility, and stability with a frequency of 0.5 MHz (f<sub>–3dB</sub>) and ultrafast rise/fall response (560ns and 230ns at –2 V) under 850nm LED light. We demonstrated highly sensitive devices with photoresponse covering from the ultraviolet to near-infrared regions. The inferior compatibility originating from the intermolecular interaction between PffBT4T-2OD and IEICO-4F allowed manipulate the degree of phase donor and acceptor separation for well-defined phase segregation, leading to efficient charge separation, transport, and collection in ternary blends. We demonstrated the transmissive pulse oximetry by integrated our OPD and the LED and precisely calculated and collected the pulse oximetry.